Convertible roof apparatus with power roof bow linked to a tensioning bow

ABSTRACT

A convertible roof actuation mechanism includes at least a forward bow, a power actuated rearmost bow and an intermediate bow. A linkage set separately connects the rearmost bow to the intermediate bow. When the forward bow is latched and as the rearmost bow is rearwardly rotated, the linkage set rotates the intermediate bow to tension the roof cover.

BACKGROUND AND SUMMARY OF THE INVENTION

[0001] The present invention relates generally to convertible roofs forautomobile vehicles and more specifically to a mechanism to tension aconvertible roof.

[0002] Vehicle soft tops or pliable convertible roofs, hereinafterreferred to as pliable roofs, are commonly supported using a pluralityof cross-car elongated support members, or “roof bows”. The roof bowsare commonly connected to the vehicle by a top stack assembly, havinglinks, rotating connections and support elements. To tension, thepliable roof is often raised from a folded or stowed position until aforward-most roof bow is adjacent the vehicle windshield structure. Thepliable roof or forward-most roof bow is latched to the vehiclewindshield structure. A rear-most roof bow is commonly connected to arear structure of the vehicle. For power actuated pliable roofs, anintermediate roof bow is commonly connected to an actuator, such as ahydraulic or mechanical actuator. The actuator rotates the connectedroof bow and, via the top stack assembly, the remaining pliable roofsections to an upright and tensioned position. A disadvantage of thesesystems is the potential to damage the pliable roof by over-rotation orunder-rotation of the powered intermediate roof bow. Still anotherdisadvantage is that a backlite section positioned in the rear of thepliable roof can be under-tensioned causing the backlite to vibrateduring travel.

[0003] In accordance with the preferred embodiment of the presentinvention, a convertible roof actuation mechanism includes at least aforward bow, a power actuated rearmost bow and an intermediate bow,having a linkage set connecting the rearmost bow to the intermediatebow. In another aspect of the present invention, when the forward bow islatched and as the rearmost bow is rearwardly rotated, the linkage setrotates the intermediate bow to tension the roof cover.

[0004] In another embodiment, a pliable roof cover is supported by aplurality of roof bows. A linkage set connectably joins a rear-most bowto an intermediate bow. After a forward-most bow is connected to avehicle windshield structure, the rear-most bow is positioned adjacentto a vehicle rear structure by an actuator device. The linkage setrotatably positions the intermediate bow in a roof cover tensionedposition. In yet another embodiment, a convertible roof tensioningsystem includes five roof bows and a linkage set connecting a numberfour bow to a powered number five bow. In still another embodiment, amethod to tension a convertible roof cover is provided.

[0005] The invention offers several advantages. A linkage set connectinga rearmost roof bow to a next adjacent roof bow allows the poweredactuation of the rearmost roof bow to position the next adjacent roofbow, thereby tensioning the roof. All further forward roof bows can bepre-positioned and a forward-most bow latched to windshield structureprior to location of the rearmost bow and tensioning of the pliableroof. Further areas of applicability of the present invention willbecome apparent from the detailed description and claims providedhereinafter, taken into conjunction with the accompanying drawings. Itshould be understood that the detailed description and specificexamples, while indicating the preferred embodiment of the invention,are intended for purposes of illustration only and are not intended tolimit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

[0007]FIG. 1 is a side elevation view of an automotive vehicleincorporating a convertible roof actuation system having a powered roofbow linked to a tensioning roof bow according to a preferred embodimentof the present invention;

[0008]FIG. 2 is a side diagrammatic view showing a portion of the roofmechanism of the present invention;

[0009]FIG. 3 is a perspective view looking generally forward, detailingthe linkage set of the present invention;

[0010]FIG. 4 is an side diagrammatic view of a partially foldedconvertible roof having the linkage set of the present invention;

[0011]FIG. 5 is a cross-sectional view of an exemplary link-to-link,link-to-bracket, connector-to-bracket, or link-to-connector rotatablejoint for the linkage set of the present invention;

[0012]FIG. 6 is a cross-sectional view showing an exemplarylink-to-spacer-to-connector rotatable joint for the linkage set of thepresent invention; and

[0013]FIG. 7 is a flow diagram identifying the steps to tension aconvertible roof using a convertible roof actuation system of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0014] The following description of the preferred embodiment is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

[0015] According to a preferred embodiment of the present invention, aconvertible roof actuation system 10 includes a pliable roof 12connectably attached to an automobile 14. A top stack assembly 16 isused to deploy the pliable roof 12 between a closed and a fully openposition (shown). Pliable roof 12 is supported by five roof bowsincluding a forward-most or number one bow 18, a number two bow 20, anumber three bow 22, at least one intermediate or number four bow 24,and a rear-most or number five bow 26. Number one bow 18 is latched to awindshield structure 28 via a latch mechanism 30 in the fully openposition of pliable roof 12 and can be latched either automatically ormanually. Number five bow 26 contacts a rear structural area 32 in thefully open position of pliable roof 12. Pliable roof 12 also includes abacklight 34 disposed between number four bow 24 and number five bow 26.Opposed sides of pliable roof 12 are supported by/connected toautomobile 14 via each of a pair of rear rails 36.

[0016] Referring next to FIG. 2, a linkage set 38 according to thepreferred embodiment of the present invention is shown. Linkage set 38connects number five bow 26 to number four bow 24 and is bothconnectable and moveable independent of top stack assembly 16. Numberfive bow 26 is rotatably supported such that number five bow 26 rotatesthrough an arc “A” about center-of-rotation “B”. Number five bow 26 isrotatably supported to rear rail 36 by a pinned joint formingcenter-of-rotation “B”. Actuation of pliable roof 12 is by a pair ofhydraulic actuators 40 (only one hydraulic actuator 40 is shown forclarity). Each of the pair of hydraulic actuators 40 is rotatablyconnected at both a first end to structure of one of the pair of rearrails 36, and at a second end to number five bow 26. Each hydraulicactuator 40 includes a piston/cylinder having the first end and a driverod including the second end. A hydraulically actuated rear-most ornumber five bow for a convertible roof system is disclosed in U.S.patent application Ser. No. 09/965,109, filed Sep. 26, 2001, entitled“Top Stack Mechanism for a Convertible Roof”, the disclosure of which isincorporated herein by reference.

[0017] Elements of top stack assembly 16 are also shown in FIG. 2. Sucha top stack assembly is disclosed in U.S. Pat. No. 5,998,948, entitled“Convertible Roof Actuation Mechanism” which issued to Piontek et al. onJun. 27, 1995, and is assigned to the assignee of the present invention,the disclosure of which is incorporated herein by reference. In thefully open or fully deployed position shown in FIG. 2 for pliable roof12, number five bow 26 is fully rotated in a clockwise direction aboutarc “A” such that number five bow 26 contacts rear structural area 32(shown in FIG. 1). Linkage set 38, connected between number five bow 26and number four bow 24, rotatably positions number four bow to fullytension pliable roof 12 in the “roof tensioned position” shown in FIGS.1 and 2.

[0018] As best seen in FIG. 3, linkage set 38 includes a first link 42having a first end 44, an intermediate location 46, and a second end 48.A second link 50 includes a first end 52, an intermediate location 54,and a second end 56. A bracket 58 includes a bracket first end 60, abracket intermediate location 62, and a bracket second end 64. Aconnector 66 includes a connector first end 68 and a connector secondend 70. Pin connectors for the rotatable joints joining members oflinkage set 38 are best described in reference to FIGS. 5 and 6.

[0019] Linkage set 38 is formed as follows. First end 44 of first link42 is rotatably pinned to number five bow 26. Intermediate location 46of first link 42 is rotatably connected to connector first end 68 via apin rotatably supported between first link 42 and connector 66 via aspacer 71. Second end 48 of first link 42 is rotatably connected tointermediate location 54 of second link 50. This connection is notclearly visible in FIG. 3 and is shown in further detail in reference toFIG. 4. Number five bow 26 is rotatably connected to rear rail 36 usinga clevis 72 and a pin 74. Second link 50 is rotatably connected to rearrail 36 using a clevis 76 and a pin 78. Second end 56 of second link 50is rotatably connected to bracket intermediate location 62 via a pin(not shown).

[0020] Bracket 58 is fixedly connected to number four bow 24 at bracketfirst end 60. This connection can be made by brazing, welding or otherpermanent connection techniques. Bracket 58 is rotatably connected toconnector second end 70 at bracket second end 64. A length of spacer 71is selected based on the thicknesses and clearance requirements forbracket 58 and second link 50 disposed between first link 42 andconnector 66 respectively. Linkage set 38 shown in FIG. 3 represents theleft hand set, looking generally forward of a pair of linkage sets 34supporting adjacent ends of number five bow 26 and number four bow 24. Aright hand set, not shown, is a mirrored image of FIG. 3.

[0021] As best seen in FIG. 4, linkage set 38 is shown in a fully foldedconfiguration having number five bow 26 fully rotated counterclockwise,as viewed in FIG. 4, about arc “A” (shown in FIG. 2), and number fourbow 24 disengaged from the “roof tensioned position” shown in FIG. 1. Inthe position shown in FIG. 4, the number one, number two and numberthree bows 18, 20 and 22, respectively, are positioned in their uprightpositions either prior to complete fold-up or following partial raisingof pliable roof 12 using top stack assembly 16.

[0022] As best seen in FIG. 5, an exemplary joining of two member partsof linkage set 38 is shown. Number five bow 26 is shown in cross sectionrotatably joined to first end 44 of first link 42 by a spin rivet 80.Spin rivet 80 is first passed through an aperture 82 of number five bow26 and a coaxially aligned aperture 84 of first end 44. Both aperture 82and aperture 84 are coaxially aligned along an aperture longitudinalaxis 86. Diameters for aperture 82 and aperture 84 can vary from eachother to suit alignment tolerance(s) for linkage set 38. In theembodiment shown, a head end 88 of spin rivet 80 abuts a surface ofnumber five bow 26. An engagement end 89 of spin rivet 80 is swaged orflared as shown to contact a surface of first end 44 such that numberfive bow 26 and first end 44 are rotatably joined.

[0023] Referring now to FIG. 6, a spin rivet 90, similar to spin rivet80, is shown connecting intermediate location 46 of first link 42 toconnector first end 68, via spacer 71. An aperture 92 is provided inintermediate location 46. An aperture 94 is provided through spacer 71.Similarly, an aperture 96 is provided through connector first end 68.Each of the apertures 92, 94 and 96 are coaxially aligned along apertureaxis 98 and can vary in diameter as noted above for apertures 82 and 84.In the embodiment shown, spin rivet 90 is slid into position within eachof the apertures 92, 94 and 96 such that a head end 100 engagesintermediate location 46, and an engagement end 102 (similar toengagement end 89 of spin rivet 80), is swaged or flared to engageconnector first end 68.

[0024] Alternately, spin rivets 80 and 90, shown in FIGS. 5 and 6,respectively, can have their head ends reversed from those shown ineither FIGS. 5 or 6. The location of the head ends of the spin rivetsare determined in part by the clearance requirement (including materialthickness) between linkage elements of linkage set 38. Other types ofconnectors in addition to spin rivets can also be used, including, butnot limited to pins with clips inserted through apertures at the endsthereof, standard rivets, or bolts with nuts if clearances permit.Materials for the spin rivets or similar fasteners are typicallymetallic, such as steel or aluminum, to provide good wear resistance forthe rotating parts of linkage set 38. Materials for linkage set 38 linksand brackets are preferably metals, including, but not limited to steel,stainless steel or aluminum.

[0025] Materials for the roof bows are typically metal, such asaluminum. In alternate embodiments, number one through number five bows18, 20, 22, 24 and 26, respectively, can also be molded of polymericmaterial such as nylon 6/6 and reinforced with glass fibers, or formedas a composite of materials, including unfilled nylon 6/6, chopped glassfiber filled nylon 6/6, and/or aluminum or steel. Such a molded roof bowis disclosed in U.S. Pat. No. 5,427,429, entitled “Convertible Top Bow”which issued to Piontek et al. on Jun. 27, 1995, and is assigned to theassignee of the present invention, the disclosure of which isincorporated herein by reference. Such a composite roof bow is disclosedin U.S. Pat. No. 6,282,791 B1, entitled “Method of Making an AutomotiveVehicle Convertible Roof” which issued to Patelczyk on Sep. 4, 2001, andis assigned to the assignee of the present invention, the disclosure ofwhich is incorporated herein by reference. Material for the pliable roof12 can be of a pliable fabric, elastomeric, or composite material.

[0026] An exemplary operation of a vehicle convertible roof having aconvertible roof actuation system 10 of the present invention is asfollows. Pliable roof 12 is initially in a completely folded and stowedposition in a rear area of the vehicle. Hydraulic actuators 40 areactuated to rotate pliable roof 12 using top stack assembly 16 to anintermediate position shown in FIG. 4. Number one bow 26 is latched towindshield structure 28, either manually or automatically. Hydraulicactuators 40 are further actuated to rotate pliable roof 12 through arc“A” and about center-of-rotation “B” shown in FIG. 2, in a generallyclockwise direction as viewed in FIG. 2, until number five bow 26contacts rear structural area 32. The powered rotation of number fivebow 26 causes simultaneous rotation of number four bow 24, via linkageset 38, to support and tension pliable roof 12 in the “roof tensionedposition” shown in FIGS. 1 and 2. Number four bow 24 is thereafter heldin the “roof tensioned position” by linkage set 38, until number fivebow 26 is rotated to fold pliable roof 12. Retracting or folding pliableroof 12 is accomplished by reversing the preceding steps.

[0027] As best described in FIG. 7, in a step 200, a pliable roof coveris connected to a roof bow set having five roof bows. In joining step202, a next adjacent one of the roof bows is rotatably joined to arearmost roof bow with a linkage mechanism. In step 204, an actuator isenergized to drive the rearmost one of the roof bows in a rearward, roofopening motion. In a following step 206, the next adjacent roof bow isrotated with the linkage mechanism to tension the pliable roof cover.Next, in a parallel step 208, a forward-most one of the roof bows islatched prior to the energizing step. In a preceding parallel step 210,the forward-most one of the roof bows is positioned adjacent awindshield structure prior to the latching step. At step 212, the roofcover is initially raised having the next adjacent roof bow foldedadjacent to the rearmost roof bow. In step 214, each of the roof bows isconnected to a top stack assembly, independent of the linkage mechanism.Finally, in a step 216, the actuator is coupled to only the rearmostroof bow, independent of the linkage mechanism.

[0028] A convertible roof actuation system of the present inventionoffers several advantages. By mechanically linking the number four bowto a power actuated number five bow the number four bow can be rotatedto a position which tensions the roof during final placement of thenumber five bow. Tensioning a pliable roof with a number four bow usinga convertible roof actuation system of the present invention permitseach of the remaining bows to be prepositioned and the number one bowlatched to the windshield structure prior to location of the number fivebow and tensioning of the pliable roof.

[0029] A convertible roof actuation system of the present invention isnot limited by the specific embodiment of the linkage set shown anddescribed herein. Modifications to the linkage set of the presentinvention can be made without departing from the gist of the presentinvention, providing that the powered rearmost roof bow is rotatablylinked to the next adjacent roof bow, therefore using the next adjacentroof bow to tension the pliable roof of the vehicle. Additionally, aconvertible roof actuation system of the present invention is notlimited by the number of roof bows. The invention is applicable to avehicle roof having three or more roof bows, providing that a poweredrearmost roof bow is rotatably linked to the next adjacent roof bow. Thedescription of the invention is merely exemplary in nature and, thus,variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A convertible roof actuation mechanism for an automotive vehicle, themechanism comprising: a top stack assembly having a plurality ofmoveable roof bows, including at least a forward bow, a power actuatedrearmost bow and an intermediate bow located between the forward and therearmost bows; a pliable roof cover connectable to the top stackassembly; and at least one linkage set moveable independent of the topstack assembly connecting the rearmost bow to the intermediate bow;wherein when the forward bow is in a raised/latched position and therearmost bow is rearwardly power actuated, the intermediate bow ismoveable by the linkage set to a roof cover tensioned position.
 2. Themechanism of claim 1, comprising a hydraulic actuator connectable to therearmost bow.
 3. The mechanism of claim 2, wherein the hydraulicactuator comprises a pair of hydraulic piston/cylinders, eachconnectable to one of an opposed pair of sides of the rearmost bow. 4.The mechanism of claim 1, wherein at least the rearmost and theintermediate bows each comprise an opposed pair of sides connectablyjoined by a central member.
 5. The mechanism of claim 4, wherein thelinkage set comprises at least a pair of mechanisms, each mechanismrotatably connecting adjacent portions of the rearmost and theintermediate bows.
 6. The mechanism of claim 1, further comprising apair of support bows positioned between the intermediate bow and theforward bow.
 7. The mechanism of claim 1, wherein each of the roof bowsis longitudinally positionable in a cross-car orientation.
 8. Themechanism of claim 1, wherein each linkage set comprises: a first linkhaving a first end, an intermediate location and a second end, the firstlink rotatably connectable to the rearmost bow at the first link firstend; a second link having a first end, an intermediate location and asecond end, the second link rotatably connectable to a rear rail at thesecond link first end; a fastener rotatably connecting together thefirst link second end and the second link intermediate location; abracket having a bracket first end fixedly connected to the intermediatebow, a bracket intermediate location rotatably connected to the secondlink second end, and a bracket second end; and a connector having afirst end rotatably connectable to the first link intermediate locationand a second end rotatably connectable to the bracket second end.
 9. Aconvertible roof system for an automotive vehicle, the systemcomprising: a pliable roof cover; a plurality of roof bows adaptable tosupport the roof cover, the plurality of roof bows including at least aforward-most bow latchable to the vehicle, a rear-most bow, and anintermediate bow positioned between the forward-most bow and therear-most bow; at least a pair of actuators connectable to at least therear-most bow; and a linkage set connectably joining the rear-most bowto the intermediate bow; wherein when the rear-most bow is rearwardlypositioned by the pair of actuators, the intermediate bow and thepliable roof cover are moveably positioned by the linkage set in a roofcover tensioned position.
 10. The roof system of claim 9, wherein theplurality of roof bows comprises a quantity of five roof bows.
 11. Theroof system of claim 10, wherein the quantity of five roof bows furthercomprises a pair of roof bows located between the forward-most bow andthe intermediate bow.
 12. The roof system of claim 10, comprising a roofcover stowed position having the plurality of roof bows adjacentlyfolded about the top stack assembly.
 13. The roof system of claim 9,comprising an opposed pair of sides of the rear-most bow eachconnectably attached to one of the pair of actuators.
 14. The roofsystem of claim 9, comprising a top stack assembly interlinking each ofthe roof bows, independent of the linkage set.
 15. The roof system ofclaim 9, comprising a roof cover semi-open position having both therear-most bow and the intermediate bow adjacently folded about thelinkage set, and remaining ones of the plurality of roof bows in fullyextended positions.
 16. A convertible roof tensioning system for anautomotive vehicle, said system comprising: a roof bow set having atleast five roof bows each elongated in a substantially cross cardirection, and each interlinked by a top stack linkage system, the roofbow set including a number one bow releasably connectable to thevehicle, a number four bow rearwardly located from the number one bowwhen raised, and a number five bow rearwardly located from the numberfour bow when raised; an automatic actuator system directly connectableto the number five bow; and a mechanism joining the number five bow andthe number four bow such that when the number five bow is moved from afirst partially extended position to a second fully extended position bythe actuator system, the number four bow is movable to a roof tensionedposition by the mechanism.
 17. The tensioning system of claim 16,comprising a plurality of fasteners for connectably joining the numberfive bow to the number four bow with the mechanism.
 18. The tensioningsystem of claim 17, wherein the plurality of fasteners comprises atleast one pin and clevis pair.
 19. The tensioning system of claim 17,wherein the plurality of fasteners comprises at least one rivet.
 20. Thetensioning system of claim 16, wherein the actuator system comprises apair of hydraulic actuators.
 21. The tensioning system of claim 20,wherein each of the hydraulic actuators includes a rotatable connectorjoined to the number five bow.
 22. The tensioning system of claim 16,comprising: a number two bow rearwardly located from the number one bow;and a number three bow rearwardly located from the number two bow andforwardly located from the number four bow.
 23. The tensioning system ofclaim 16, wherein the mechanism comprises a plurality of links eachformed of a metal material.
 24. A mechanically linked retractable roofsystem for an automotive vehicle, the system comprising: (a) a top stacklinkage mechanism having opposed side rails; (b) at least three roofbows spanning between the side rails, including a forward-most roof bow,a rearmost roof bow and an intermediate roof bow positioned immediatelyforward of the rearmost roof bow when raised; and (c) a pair ofconnecting mechanisms operable independent of the top stack mechanism,the connecting mechanisms moveably joining the rearmost roof bow to theintermediate roof bow, each of the connecting mechanisms including: (i)a first link connectable to the rearmost roof bow; (ii) a second linkconnectable to both the first link and one of the side rails; (iii) abracket connectable to both the intermediate roof bow and the secondlink; and (iv) a connector operably joining the first link to a bracketsecond end.
 25. The roof system of claim 24, wherein each of theconnecting mechanisms further comprise: a bracket first end fixedlyconnectable to the intermediate roof bow; a bracket intermediatelocation rotatably connectable to the second link; a connector first endrotatably connectable to the first link at a first link intermediatelocation; and a connector second end rotatably connectable to thebracket second end.
 26. A method for operating a convertible roof of anautomotive vehicle, the roof including a pliable roof cover connected toa plurality of roof bows, a rearmost one of the roof bows rotatablyjoined to a next adjacent one of the roof bows with a linkage mechanism,the method comprising: raising the convertible roof from a stowedposition to an intermediate position; energizing an actuator to drivethe rearmost roof bow in a rearward, roof extending motion; and rotatingthe next adjacent roof bow with the linkage mechanism to tension thepliable roof cover.
 27. The method of claim 26, comprising latching aforward-most one of the roof bows prior to the energizing step.
 28. Themethod of claim 27, comprising positioning the forward-most one of theroof bows adjacent a windshield structure prior to the latching step.29. The method of claim 27, comprising: unlatching the forward-most oneof the roof bows following the rotating step; and returning theconvertible roof to the stowed position using the actuator.
 30. Themethod of claim 26, comprising initially raising the roof cover havingthe next adjacent one of the roof bows folded adjacent to the rearmostone of the roof bows.
 31. The method of claim 26, comprising spacingeach of the roof bows using a top stack assembly during the raisingstep, independent of the linkage mechanism.
 32. A convertible roofactuation mechanism for an automotive vehicle, the mechanism comprising:a pliable roof cover; a plurality of roof bows adaptable to support theroof cover, the plurality of roof bows including at least a forward-mostbow latchable to the vehicle, a rear-most bow, and an intermediate bowpositioned between the forward-most bow and the rear-most bow; and alinkage set connectably joining the rear-most bow to the intermediatebow; wherein when the rear-most bow is rearwardly positioned theintermediate bow and the pliable roof cover are moveably positioned bythe linkage set in a roof cover tensioned position.
 33. The mechanism ofclaim 32, wherein the plurality of roof bows comprises a total quantityof five roof bows.
 34. The mechanism of claim 33, wherein the totalquantity of five roof bows further comprises a pair of roof bows locatedbetween the forward-most bow and the intermediate bow.
 35. The mechanismof claim 32, comprising a roof cover stowed position having theplurality of roof bows adjacently folded about the linkage set.
 36. Themechanism of claim 35, further comprising: a pair of actuators; and anopposed pair of sides of the rear-most bow each connectably attached toone of the pair of actuators; wherein the pair of actuators are operableto position the roof cover between each of the stowed position and theroof cover tensioned position.
 37. The mechanism of claim 32, comprisinga top stack assembly interlinking each of the roof bows, independent ofthe linkage set.
 38. The mechanism of claim 32, comprising a roof coversemi-open position having both the rear-most bow and the intermediatebow adjacently folded about the linkage set, and remaining ones of theplurality of roof bows each in a fully extended position.
 39. Aconvertible roof actuation mechanism for an automotive vehicle, themechanism comprising: a roof bow set having a plurality of roof bowseach elongated in a substantially cross car direction; a top stackassembly interlinking each of the roof bows; and a mechanism joining arearmost one of the roof bows to an adjacent one of the roof bows;wherein when the rearmost bow is moved from a first partially extendedposition to a second fully extended position, the adjacent one of theroof bows is movable to a roof tensioned position by the mechanism. 40.The mechanism of claim 39, wherein the roof bow set further comprises: anumber one bow releasably connectable to the vehicle; a number two bowrearwardly located from the number one bow; and a number three bowrearwardly located from the number two bow and forwardly located fromthe adjacent roof bow.
 41. The mechanism of claim 40, comprising aplurality of fasteners for connectably joining the rearmost bow to theadjacent bow with the mechanism.
 42. The mechanism of claim 41, whereinthe plurality of fasteners comprises at least one pin and clevis pair.43. The mechanism of claim 41, wherein the plurality of fastenerscomprises at least one rivet.
 44. The mechanism of claim 39, furthercomprising an automatic actuator system directly connectable to therearmost bow, wherein the actuator system includes a pair of hydraulicactuators.
 45. The mechanism of claim 44, wherein each of the hydraulicactuators includes a rotatable connector joined to the rearmost bow. 46.The mechanism of claim 39, wherein the top stack linkage system furthercomprises a plurality of links each formed of a metal material.
 47. Themechanism of claim 39, further comprising: an opposed pair of side railsof the top stack assembly; and the mechanism including a pair ofconnecting mechanisms operable independent of the top stack assembly,the connecting mechanisms moveably joining the rearmost bow to theintermediate bow, each of the connecting mechanisms including: (a) afirst link connectable to the rearmost bow; (b) a second linkconnectable to both the first link and one of the side rails; (c) abracket connectable to both the intermediate roof bow and the secondlink; and (d) a connector operably joining the first link to a bracketsecond end.